When I select several items in list view, action button is supposed to appear on top of the page, but nothing happens.

This affects all list views (contacts, leads, opportunities, users etc). 

Looking at the demo on Odoo site, the div class=o_cp_action_menus should appear in DOM, but in my case, nothing appears on the page.

No error messages in console.

We didn't do any customization regrading action buttons. I think this was the way since the beginning, but don't remember for sure.

Problem persist for different user's permission levels, browsers, computers.

Odoo version: Odoo 14.0-20210226 (Community Edition)

Any idea what may be causing it? Anywhere to look for clues?

Thanks!